Reviewed by USGS13y ago
M7.3 earthquake in South Sandwich Islands region
Monday, July 15, 2013, 14:03:39 UTC · 60.857°S, 25.070°W
A magnitude 7.3 earthquake struck in South Sandwich Islands region on Monday, July 15, 2013, 14:03:39 UTC, at a depth of 11.0 km (shallow). The USGS PAGER alert is green: low likelihood of casualties and damage. It is the strongest earthquake within 300 km since an M7.4 on January 2, 2006.
Tsunami flagUSGS sets this flag for large events in oceanic regions so tsunami warning centers review them. It does not by itself mean a tsunami occurred. Check tsunami.gov and local authorities for official messages.
- Magnitude
- 7.3
- Major · mww
- Depth
- 11 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- VI
- Strong (ShakeMap)
- PAGER alert
- Green
- Impact estimate
- Tsunami
- Flag
- Check tsunami.gov
Outlined circle: this earthquakeDashed circle: 200 km aftershock search area
In context
How big was it, and why here?
Energy released
1.3 megatons of TNT
That is about 89 times the Hiroshima bomb. It released about 2,818 times the energy of a magnitude 5.0.
Tectonic setting
22 km
from the nearest mapped plate boundary, between the Australian and Antarctic plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
11 km
Shallow earthquakes (under 70 km) produce the strongest surface shaking for their size, so they are the ones most likely to cause damage near the epicenter.
Did You Feel It?
Where it was felt
No “Did You Feel It?” reports have been published for this event yet. If you felt it, you can add your report on the USGS website.
I felt it — report to USGS ↗USGS PAGER estimate
Who was exposed to shaking
USGS publishes PAGER impact estimates for significant earthquakes, usually within an hour. No populated area was estimated to feel noticeable shaking.
After the main event
Aftershocks within 200 km
USGS lists 10 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M5.1 on July 16, 2013. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
- 4.4South Sandwich Islands region13y ago · 120 km NW of this epicenter
- 4.6South Sandwich Islands region13y ago · 112 km NW of this epicenter
- 4.7South Sandwich Islands region13y ago · 108 km NW of this epicenter
- 4.6South Sandwich Islands region13y ago · 17 km N of this epicenter
- 5.0South Sandwich Islands region13y ago · 85 km NW of this epicenter
- 4.6South Sandwich Islands region13y ago · 79 km SE of this epicenter
- 5.1South Sandwich Islands region13y ago · 128 km NW of this epicenter
- 4.7South Sandwich Islands region13y ago · 28 km E of this epicenter
Regional history
Past M5+ earthquakes within 300 km
USGS lists 485 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.5South Sandwich Islands regionAugust 28, 1933 · 129 km NW of this epicenter
- 7.4east of the South Sandwich IslandsJanuary 2, 2006 · 188 km E of this epicenter
- 7.3South Sandwich Islands regionSeptember 1, 1961 · 201 km NW of this epicenter
- 7.2South Sandwich Islands regionNovember 15, 1910 · 204 km N of this epicenter
- 7.2South Sandwich Islands regionOctober 22, 1983 · 30 km NW of this epicenter
- 7.1east of the South Sandwich IslandsAugust 26, 1977 · 298 km NE of this epicenter
- 7.0east of the South Sandwich IslandsOctober 6, 1973 · 191 km E of this epicenter
- 7.0South Sandwich Islands regionJanuary 30, 1987 · 134 km NW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 2 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1961M7.5
South Sandwich Islands
1 Sep 1961 · 195 km away
- 1973M7.5
Antarctica
6 Oct 1973 · 191 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.